title: A Reovirus Causes Hypovirulence of Rosellinia necatrix.
abstract: ABSTRACT White root rot, caused by Rosellinia necatrix, is a serious soilborne disease of fruit trees and other woody plants. R. necatrix isolate W370 contains 12 segments of double-stranded RNA (dsRNA) that is believed to represent a possible member of the family Reoviridae. W370 was weakly virulent and its hyphal-tip strains became dsRNA free and strongly virulent. The 12 segments of W370dsRNA were transmitted to hygromycin B-resistant strain RT37-1, derived from a dsRNA-free strain of W370 in all or none fashion through hyphal contact with W370. The W370dsRNA-transmitted strains were less virulent than their parent strain RT37-1 on apple seedlings, with mortality ranging between 0 to 16.7% in apple seedlings that were inoculated with the W370dsRNA-containing strains and 50 to 100% for seedlings inoculated with the dsRNA-free strains. Some W370dsRNA-containing strains killed greater than 16.7% of seedlings, but these were found to have lost the dsRNA in planta. These results indicate that W370dsRNA is a hypovirulence factor in R. necatrix. In addition, a strain lost one segment (S8) of W370dsRNA during subculture, and the S8-deficient mutant strain also exhibits hypovirulence in R. necatrix.
authors.forename: S
authors.initials: S
authors.lastname: Kanematsu
authors.forename: M
authors.initials: M
authors.lastname: Arakawa
authors.forename: Y
authors.initials: Y
authors.lastname: Oikawa
authors.forename: M
authors.initials: M
authors.lastname: Onoue
authors.forename: H
authors.initials: H
authors.lastname: Osaki
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: Y
authors.initials: Y
authors.lastname: Kuga-Uetake
authors.forename: H
authors.initials: H
authors.lastname: Nitta
authors.forename: A
authors.initials: A
authors.lastname: Sasaki
authors.forename: K
authors.initials: K
authors.lastname: Suzaki
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: N
authors.initials: N
authors.lastname: Matsumoto